Crankpin grinding machine



May 31, 1949. A. v. SPONGBERG ET AL ,7

-CRANKPIN GRINDING MACHINE Filed Feb. '7, 1946 4 Sheets-Sheet lgluon-HIM HA WW 6. PASHO m 3 3 M LO. W F] 1 May 31, 1949.

' Filed Feb. 7, 1946 A. v. SPONGBERG T L 2,471,706

CRANKPIN GRINDING MACHINE 4 Sheets-Sheet 2 25 27 54 53 37 I 5 4 as E 8 TFig. 3

gvwa/wtom ALBIN SPONGBERG HARRY G. PASHOIAN y 1, 1949. A. v. SPONGBERGET AL 2,471,706

CRANKPIN GRINDING MACHINE Filed Feb. 7, 1946 4 Sheets-Sheet 3 55 Flg. 5v grwe/rm ALBIN 5PONGBERG HARRY GPAsHOIAN Wm-wm WW y 1949. A. v.SPONGBERG ET AL 2,471,706

CRANKPIN GRINDING MACHINE Filed Feb. 7, 1946 4 Sheets-Sheet 4 ALBINSPONGBERG 3% HARRY GPA5}-\0\AN Patented May 31, 1949 UNITED STATESPATENT OFFICE CRANKPIN GRINDING MACHINE Albin V. Spongberg and Harry G.Pashoian, Worcester, Mass, assignors'to Norton Company, Worcester,Mass., a corporation ofMassachusetts Application February 7, 1946,Serial No. 645,988

Claims. 1 This invention relates to grinding machines, and moreparticularly to a double head crank pin grinding machine.

One of the objects of this invention is to provide a readilycontrollable crank pin grinding machine. Another object is to provide acrank pin grinding machine with a pair of opposed aligned pot chucksfor-supporting and synchronously rotating the opposite ends of a crankshaft.

Another object of the invention is to provide acontrol valve forcontrolling the admission to and exhaust of fluid from the hydraulicallyoperated pot chucks. Another object of the invention is to provide acontrol valve which is arranged so that if the fluid pressure fails, thevalve will automatically close to lock a column of fluid within the workclamping mechanism so that the clamp will not be released.

A further object of the invention is to provide a pot chuck controlvalve which is inter-connected with the main control valve of themachine so that when a grinding operation has been completed and themain control valve shifted to cause a rearward movement of the wheelslide, the pot chuck control valve will be shifted under the influenceof fluid under pressure to allow fluid to exhaust from the clampingcylinders and thereby to release the clamping jaw to facilitate aloading operation. Other objects will be apparent from the foregoingdisclosure.

This invention accordingly consists in the fee.-

tures of construction, combinations of elements,

and arrangements of parts as will be exemplified in the structure to behereinafter described, and

the scope of the application of which will beindicated in the followingclaims.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of the invention,

Fig. 1 is a front elevation of a crank pin grinding machine embodyingthe invention;

Fig. 2 is a vertical sectional view, on an enlarged scale, through theright hand work head showing the hydraulic work clamping mechanism;

Fig. 3 is an end elevation, partly in section. on an enlarged scale, ofthe right hand pot chuck;

Fig. 4 is a cross sectional view, on an enlarged scale, takenapproximately on the line 4-4 of Fig. 2, through the control valve forcontrolling the hydraulically operated pot chucks;

Fig. 5 is a cross sectional View, taken approximately on the line 5-5 ofFig. 4; and

Fig. 6, is a hydraulic piping diagram of the hydraulic system.

A crank pin grinding machine has been illusscribed. Both of the workdriving mechanisms which supports a longitudinally movable worksupporting table H. The table II serves as a support for a work drivingand rotating mechanism comprising a pair of alignedspaced work heads l2and I3" which are each provided with rotatable spindles for supportingapair of spaced pot chucks l4 and I5 respectively.

The base It! also serves as a support for a transversely movable wheelslide l6 which is slidably transversely relative to the base In onsuitable ways (not shown). The wheel slide 16 serves as a support for arotatable grinding wheel H. The grinding wheel I! may be driven in anysuitable manner such'as, for example, an electric motor I8 mounted onthe upper surface of the wheel slide I6. The motor I8 is provided withan armature shaft I 9' which supports a multi V'-groove pulley 20. Thepulley 20' is drivingly connected by multiple V-belts 2| with a multiV'-gr0ove pulley (not shown) which is mounted on the right hand end ofthe wheel spindle to rotate the grinding wheel H.

The pot chuck I4 is mounted on the right hand end of a work head spindle22 which is rotatably journalled in bearings in the work head I2.

A work head spindle 25 is rotatably journalled in bearings 26 and 2'!which are in turn supported within the Work head l3.

A work driving mechanism is provided for synchronously rotating the workspindle 22 and 25 respectively so as to rotate the opposite ends of acrank shaft 28 to'be ground. This driving mechanism may comprise anelectric motor 3!] which is preferably mounted within the base Ill ofthe machine. The motor 30 is connected by means of a link chain 3| witha rotatable shaft 32. The shaft 32 is operatively connected by means ofa link chain" 33 to rotate the spindle 2-2. The shaft 32 is alsoprovided with a sprocket 34" which is connected'by means of a link chain35 with a sprocketBG which is-keyed to a rotatable shaft 31 journalled'Within a bearing 38. The bearing 38 is fixedly mounted within thehousing 39'; The shaft 3Tis drivingly'connected with work spindle 25 ina manner to be hereinafter deare identical and it is therefore notbelieved to be necessaryto illustrate both work driving heads andmechanisms in detail.

The pot chucks l4 and [5 are identical in construction except that onechuck is right hand and the other left hand in arrangement. Asillustrated in Fig. 3 pot chuck l5 has been shown in end elevation andpartly broken away and shown in section. This chuck |5 comprises a half.bearing member 40 which serves as a support for an end portion 4| of thecrank shaft 28. A clamping arm 42 is pivotally supported on a stud 43.The short arm of the clamping arm 42 is provided with a clamping jaw 44.The long arm of the clamping arm 42 is provided with a stud 45 which isconnected to one end of a piston rod 46. The pot chuck is provided witha hydraulic cylinder 41 which contains a slidably mounted piston 48. Thepiston 48 is connected by means of a stud 49 with the piston rod 46. Thecylinder 41 is provided with a port 50 which is arranged to admit fluidunder pressure to a cylinder chamber 5|. It will be readily apparentfrom the foregoing disclosure that when fluid is admitted to thecylinder chamber 5|, the piston 48 will move toward the right into theposition illustrated in Fig. 3. This movement rocks the clamping arm 42in a counter-clockwise direction so that the clamping jaw 44 engages andclamps the portion 4| of the crank shaft 28 into rigid engagement withthe half bearing support 40. The pot chuck I4 is identical inconstruction and consequently has not been illustrated in detail.

A universal driving connection 52 is provided between the shaft 31 (Fig.2) and the work head spindle 25. This universal connection comprises apair of diametrically opposed rollers 53 and 53a which are rotatablysupported on studs which are fixed relative to the shaft 31. The opposedrollers 53 and 53a slide in elongated slots 54 and 54a which are formedin a flanged member fixed to the spindle 25.

It is desirable to provide a suitable control valve for controlling theadmission to and exhaust of fluid from the clamping cylinder 41. Acontrol valve 55 (Figs. 4 and 5) is provided with an integral flangedmember 55 which is in turn fixedly mounted on the right hand end of thehousing 39. This control valve is preferably a piston type valve havinga slidably mounted valve member 51. The slidably mounted valve member 51comprises integral valve pistons 58 and 59 which are arranged so thatthe efiective area of the piston 59 is considerably greater than theeiTective area of the piston 58. Fluid under pressure direct from afluid pump to be hereinafter described passes through a pipe 65 and aport 6| into a valve chamber 52 formed at the right hand end of thevalve piston 58. Fluid entering the valve chamber 62 forces the valvemember 51 toward the left into the position illustrated in Fig. 4 sothat fluid under pressure entering the chamber '62 raises the ball checkvalve 63 and passes into a chamber 64, through a passage 55 into achamber 56 and then passes through a pipe 68. The pipe 68 extendsthrough the hollow work head spindle 25 and is connected at its otherend to the pot chuck 5. Fluid under pressure passing through the pipe 68passes through a passage 69 and through the port 50 into the cylinderchamber 5| to swing the clamping arm 42 in a counter-clockwise directionto clamp the work piece within the pot chuck l5.

In order to unclamp the work piece, fluid may be passed through a pipeill through a port 1| into a chamber 12 formed at the left hand end ofthe valve 55, this pressure being the same as that admitted to thechamber 62. Due to the larger effective area of the piston 59 fluidunder pressure admitted to the chamber 12 will cause the slidablymounted valve member 51 to move toward the right so that fluid from thecylinder chamber 5| may exhaust through the port 50, the passage 59, thepipe t5, the chamber 66, and out through a port 13 (Fig. 4) through avalve chamber 14 formed between the valve pistons 58 and 55 and may passout through an exhaust port 75 and pipe 1'5 which returns exhaustingfluid to the reservoir to be hereinafter described.

A similar control valve 55a is provided for controlling the admission toand exhaust of fluid from the pot chuck 4. The control valve 55a isprovided with integral flanged member 55a which is fixedly mounted onthe housing 35a. The details'oi the valve 55a have not been illustratedsince this valve is identical with valve 55 above described. Fluid underpressure from the fluid pressure pump is passed through pipe 68a toactuate the clamping jaw of the pot chuck M to clamp the left hand endof the work piece 28 in position within the pot chuck l4. When it isdesired to release the clamping jaw, fluid under pressure is passedthrough a pipe 78a to shift the control valve 55a to shift the valve toan exhaust position so that the clamping jaw of the pot chuck I4 will beunclamped.

In order to attain one of the objects of this invention it is desirableto construct the valve 550. so that in case the fluid pump fails orthere is an appreciable drop in the pressure of the fluid within thesystem, the slidably mounted valve member 51 will be moved toward theright a suiiicient distance so that the valve piston 58 closes the portconnected to the ball check valve 63 and thus looks a column of fluidwithin the passages, chambers and the cylinder chamber 5| to hold theclamping jaw 44 in a clamped position thus preventing release of thework piece from the pot chuck I5. This mechanism preferably comprises aslidably mounted sleeve 7'! which surrounds a stud 18 which is screwthreaded into the slidably mounted valve member 57. A compression spring19 surrounds the stud l8 and it is contained within apertures formedwithin the valve piston 55 and the member V1. The compression of thespring 19 is such that in case fluid pressure drops within the valvechamber 52, the compression of the spring 79 will move the slidablymounted valve member 51 toward the right until the'head of the stud 13engages the left hand end of the member 11 in which position the valvepiston 58 has closed oil the port connecting the valve chamber 82 withthe ball check valve 63 thus automatically look-- ing a column of fluidwithin the clamping cylinder 43' and the connecting passages andchambers.

It is desirable that the passage of fluid through pipes 78 and ma beautomatically controlled so that after a grinding operation has beencompleted and the wheel slide I5 moved to a rearward or inoperativeposition, fluid under pressure will be automatically conveyed throughthe pipes 75 and 10a to unclamp the pot chucks I4 and i5 respectively.In order to obtain this desired resuit the pipes It and Mia arepreferably connected with the main control valve of the ma chine whichmay be arranged substantially the same as that shown in the prior U. S.Patent to H. A. Silven No. 2,151,666, dated March 21, 1939, to whichreference may be had for details of disclosure not contained herein.

The hydraulic control system has been illustrated in Fig. 5 in which ahydraulic cylinder 85 is provided with a piston 86. The piston 86 isconnected by a piston rod 81 with the old and under pressure through apipe 89 into the" left hand end of the cylinder 85 the piston 86 willbemoved toward the rightto transmit a corresponding movement to the wheelslide I6 and grinding wheel I 1. During this movement, fluid-within theright hand chamber of the cylinder 85' may exhaust through a pipe 89. I

A main control valve 90 is provided for controlling the admission to andexhaust of fluid" fromthe wheel feed mechanism above described.

to the work clamp mechanism above described and also to actuate asteadyrest to be hereinafter described;

A vertically movable steadyrest 91 is provided which may be movedvertically to and from an operative position. The details of thissteadyrest have not been illustrated since this rest isidentical withthat shown in the prior patent to Silven above described. The steadyrest9i is connected to the lower end of a piston rod '92. A piston 93 isfixedly mounted on the upper end of the piston rod 92 and is slidablymounted within a cylinder 94. The steadyrest as illustrated in Fig. 6 isshown in an uppermost croperative position. When it is desired to lowerthe steadyrest to an inoperative position after a grinding operation,fluid under pressure from the control valve 90 is passed through thepipe 08 into a chamber formed at the upper end of the cylinder 90 tocause a downward movement of the piston 93 and the steadyrest 9|.

The table I I is arranged to be traversed longitudinally by a fluid.pressure mechanism comprising a cylinder 95' having a piston 99slida'bly mounted therein. The piston 96'is connected toa double endpiston. rod which extends through the opposite ends of the cylinder 95andis connected: to brackets. depending from the underside of the tableII. It will. be readily apparent from the foregoing disclosure that whenfluid under pressure is passed'through a .pipe 98 into a chamber formedat the left hand end of the cylinder 95;

the piston 96 together with the table II will be it. is desiredto'traverse the table II toward'the left, fluid may be admitted throughthe pipe 99 and exhausted through the pipe 98.

A control valve I00 is. provided for controlling admission to andexhaust of fluid from the table cylinder 95.

A main control lever I02 is pivotally mounted on astud I03 which is inturn mounted on a bracket I04. The bracket I04 is supported by a rockshaft I05; It-will be readily apparent from the foregoing disclosurethat the control lever I02 maybe rocked about the stud I03 so as tocontrol the position of the valve 90 in a manner substantially thesame-as that shown in theabove mentioned Silven patent and may be movedin a plane at right angles thereto about the axis of the stud I05 whichmovement serves to control the position of the valve I00.

In order to provide a self-contained fluid pressure system for themachine, a reservoir I08 is formed within the base I0 of the machine, Amotor driven fluid pressure pump I06 is operatively connected to drawfluid through pipe I01 from the reservoir I08 and to pass fluid underpressure through a pipe I09: Fluidunder'pressure in thepip'eI09pa'ssest'o. the control valve 90, the control valve I00 andsimultaneously through the pipes 60 andit0a to thecontrol valves 55- and55a to actuate the clamping jaws.

After agrinding operation hasbeen completed,

the lever [02' is rocked. in a clockwise direction about the axis of thestud I03 to move the valve "toward the right so as to passfluidunder'pressure through thepipe'88'to-m0ve the wheel slide I6 andgrindingwheel IT rearward'to an inopera tive position and at the sametime to. move: the steadyrest 9 If downwardly to an inoperative positionin a manner above described. When. the control valve 90 reaches itsextreme right hand end position; fluid under pressure will pass throughthe pipe 10 and 10a" into control valves 50 and 50a respectively tounclamp the clampso that fluid'under pressure will be passed through thepipes (i0 and 60a to actuate the clamping jaws andthereby clamp thecrank shaft within the'pot chucks: I4- and I5. After the control valve90 has moved further toward the left, fluid under pressure will bepassedzthrough the pipe 89 to cause a forward feeding movement of thegrinding wheel and after a still further movement of the: valve 90-willbe passed through a pipe IIPI to raise'the steadyrest 9| into anoperating position relative to the work In case thereis a drop in fluidpressure within the pipes 60 and 600,, the released compression of thespring 19 will close the-port so as to look a column of fluid within theclamping cylinders and thus lock the clamping. jawsin a clampedposition. After a grinding operation has been completed the lever I02may be moved in a clockwise direction to cause the grinding wheel tomove-to-an inoperative position and-the steadyrest to be lowered to aninoperative position. With the steadyrest and grinding wheel ininoperative positions, the control lever I02- may be rocked aboutthe'axis of the stud I05 to actuate the valve I00 and thereby traversethe table II to position the next crank pin in an operative positionrelativeto the grinding wheel. I1. After all of the crank pins have beenground; the control lever I02 may be rocked in a clock wise direction.to shift the main control valve 90- to its extreme right hand positionto unclamp the ground crank pin shaft.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are" successfully achieved. Asmany possible embodimerits. may be made of the above invention and asmany changes might be made in the embodiment above set forth, it is tobe understood that all matter'hereinbefore set forth, or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

We claim-:

1. In a crankpin grinding machine having a transversely movablerotatable grinding wheel, a work support including a pair of opposedaligned work heads. a rotatable spindle in each of said heads, a potchuck on the adjacent ends of each of said spindles, a pivoted clampingjaw on each of said chucks, a piston and cylinder on each of said chucksto actuate said clamping jaws, means including a fluid pressure pump tosupply fluid under pressure to each of said cylin ders, independentcontrol valve on each of said heads between the pump and the chuckcylinders, each of said control valves comprising a slidably mountedvalve piston, a port in each of said valves to convey fluid underpressure to the pot chuck cylinders, a compression spring in each ofsaid valves normally to maintain said port closed, direct fluidconnections with an end chamber in each of said valves to shift saidvalve against the compression of said springs to open said port andthereby admit fluid under pressure to actuate the clamping jaws, andfluid connections to convey fluid under pressure simultaneously to anend chamber at the other end of each of said valves to shift said valvesso as to unclamp said Jaws.

2. In a crankpin grinding machine having a transversely movablerotatable grinding wheel, a pair of opposed aligned crank heads, arotatable spindle in each of said heads, a pot chuck on the adjacentends of each of said spindles, a clamping jaw pivotally mounted on eachof said chucks, a piston and cylinder on each of said chucks to actuatesaid clamping jaws, means including a fluid pump for supplying fluidunder pressure to said cylinders, a fluid actuated control valve on eachof said heads, direct fluid connections between one end of said valveand the fluid pump normally to pass fluid under pressure direct from thepump to said cylinder, a manually operable main control valve forcontrolling the various mechanisms of the machine, and operativeconnections between said main control valve and the other end of saidfluid actuated valve, said connections being arranged so that when themain control valve is shifted to a work unclamp position, fluid underpressure is passed to shift said fluid pressure actuated control valveto out off the flow of fluid under pressure to said cylinder and to openan exhaust port to allow fluid to exhaust from said chuck cylinder andthereby to unclamp said jaw.

3. In a crankpin grinding machine having a transversely movablerotatable grinding wheel, a work support comprising a pair of alignedopposed work heads, a rotatable spindle in each of said heads, a potchuck on each of said spindles including a pivotally mounted clampingjaw and a piston and cylinder to actuate said jaw, a fluid pump, meansincluding a control valve to control the admission to and exhaust offluid from said chuck cylinder to clamp and release said clamping jaw, aspring normally to maintain said valve in a closed position, directconnections between the fluid pump and said valve to open said valve andclamp said jaw to hold a crankshaft in said chuck, and fluid connectionsto close said valve after a grinding operation has been completed so asto exhaust fluid from the chuck cylinder and thereby unclamp said jaw torelease the finished crankshaft.

4. In a crankpin grinding machine having a transversely movablerotatable grinding wheel, a work support comprising a pair of alignedopposed work heads, a rotatable spindle in each of said heads, a potchuck on each of said spindles including a pivotally mounted claimpingjaw and a piston and cylinder to actuate said jaw, a piston type controlvalve including a slidably mounted valve member having a pair of spacedpistons each having differential efiective piston areas, a valve chamberin the opposite ends of said valve, a port in the end chamber adjacentto the smaller piston area which is connected to convey fluid underpressure to said chuck cylinder, a compression spring normally tomaintain said port closed, direct fluid connections between said pumpand said chamber to supply fluid under pressure to open said portagainst the compression of said spring so as to actuate said; clampingjaw, an exhaust port in said valve toi exhaust fluid from said chuckcylinder which is closed while pressure is supplied to hold the clampingjaw in a clamped position, and connections between a main control valveand the valve chamber adjacent to the larger piston area to shift saidvalve piston so as to close said port and open said exhaust port after agrinding operation has been completed to release said clamping jaw.

5. In a crankpin grinding machine having a transversely movablerotatable grinding wheel, a work support comprising a pair of alignedopposed work heads, a rotatable spindle in each of said heads, a potchuck on each of said spindles including a pivotally mounted jaw and apiston and cylinder to actuate said jaw, a fluid pump, a piston typecontrol valve including a slidably mounted valve member having a pair ofspaced pistons each having differential efiective piston areas, a valvechamber in opposite ends of said valve, a port in the end chamberadjacent to the smaller piston area which is connected to convey fluidunder pressure to said chuck cylinder, a compression spring normally tomaintain :said port closed, direct fluid connections between said pumpand said chamber to supply fluid under pressure to open said portagainst the compression of said spring so as to actuate said clampingjaw, an exhaust port in said valve to exhaust fluid from said chuckcylinder which is closed when pressure is supplied to hold the clampingjaw in a clamped position, and connections between a main control valveand the valve chamber adjacent to the larger piston area to shift saidvalve piston so as to close said port and open said exhaust port after agrinding operation has been completed to release said clamping jaw, saidspring being arranged to close said pressure port and thereby preventrelease of the clamping jaw in case of failure of fluid pressure.

ALBIN V. SPONGBERG. HARRY G. PASHOIAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 509,992 Wood Dec. 5, 1893 993,967Debauche May 30, 1911 1,755,937 Steiner Apr. 22, 1930 FOREIGN PATENTSNumber Country Date 687,096 Germany Jan. 22, 1940

